Surface-protective pressure-sensitive adhesive sheet

ABSTRACT

The pressure-sensitive adhesive sheet for surface protection has a three-layered film formed by laminating a layer A, a layer B and a layer C in this order and a pressure-sensitive adhesive layer formed on the layer C; wherein the layer A contains a polyethylene in an amount of at least 60% by weight based on a total weight of the layer A; the layer B contains a polypropylene type polymer in an amount of at least 50% by weight of based on a total weight of the layer B; and the layer C contains a hydrogenated styrene/diene type hydrocarbon copolymer in an amount of at least 10% by weight based on the total weight of the layer C. This sheet has excellent weathering resistance to undergo neither chalking nor fracture in the substrate at peeling, even after a prolonged outdoor exposure, develops less corona odor to enable extended operation of applying it, and can be manufactured inexpensively with reduced manufacturing process, since no anchor coat treating procedure is required.

TECHNICAL FIELD

The present invention relates to a pressure-sensitive adhesive sheet forsurface protection which has excellent weathering resistance to undergoneither chalking nor fracture in the substrate at peeling, even after aprolonged outdoor exposure, which develops less corona odor to enableextended operation of applying it, and which can be manufacturedinexpensively with reduced manufacturing process, since no anchor coattreating procedure is required.

BACKGROUND ART

Techniques for protecting a top coating surface formed on the surface ofa body of a finish-coated car are disclosed, for example, in JapaneseProvisional Patent Publication Nos. Hei 8-143830 and Hei 8-143838 andJapanese Patent Application No. Hei 9-322574. These techniquespredominantly use application of pressure-sensitive adhesive sheets forprotecting directly to coating surfaces. Such pressure-sensitiveadhesive sheets each uses as a substrate a polypropylene type film inview of its strength, flexibility, thermal resistance, etc. However,polypropylene type films undergo chalking when subjected to long outdoorexposure to cause dusting at peeling to litter the surfaces of carbodies with white powder particles, disadvantageously. In addition,polypropylene type films develop strong scorching odor due to coronadischarge treatment applied to them for securing adhesion with a releaseagent, an anchor coating agent, a pressure-sensitive adhesive, etc.,which remains considerably after pressure-sensitive adhesive sheets arecompleted. This gives rise to problems of injuring health of operatorsthat they are suffered from headache and the like induced by such odorif they carry out application for an extended period.

It is an objective of the present invention to provide a pressuresensitive adhesive sheet for surface protection which has excellentweathering resistance to undergo neither chalking nor fracture in thesubstrate at peeling, even after a prolonged outdoor exposure, whichdevelops less corona odor to enable extended operation of applying it,and which can be manufactured inexpensively with reduced manufacturingprocess, since no anchor coat treating procedure is required.

DISCLOSURE OF THE INVENTION

The present invention (1) relates to a pressure-sensitive adhesive sheetfor surface protection having a three-layered film in which a layer A, alayer B and a layer C have been laminated in this order and apressure-sensitive adhesive layer on the layer C; wherein the layer Acontains a polyethylene in an amount of at least 60% by weight based onthe total weight of the layer A; the layer B contains a polypropylenetype polymer in an amount of at least 50% by weight based on the totalweight of the layer B; and the layer C contains a hydrogenatedstyrene/diene type hydrocarbon copolymer in an amount of at least 10% byweight based on the total weight of the layer C.

The present invention (2) relates also to the pressure-sensitiveadhesive sheet for surface protection (1), wherein the layer C containsan ultraviolet stabilizer in an amount of not less than 0.1 part byweight per 100 parts by weight of the hydrogenated styrene/diene typehydrocarbon copolymer contained in the layer C and not more than 0.5% byweight based on the total weight of the layer C.

The present invention (3) relates also to the pressure-sensitiveadhesive sheet for surface protection (1 or 2), wherein at least onelayer in the three-layered film contains titanium dioxide, and thethree-layered film has a total titanium dioxide content of 5 to 20% byweight based on the total weight of the three-layered film.

The present invention (4) relates also to the pressure-sensitiveadhesive sheet for surface protection (3), wherein the layers containingtitanium dioxide all further contain an ultraviolet stabilizer, and eachtitanium dioxide-containing layer contains the ultraviolet stabilizer inan amount of not less than 0.5 part by weight per 100 parts by weight ofthe titanium dioxide contained in that layer and not more than 0.5% byweight based on the total weight of that layer.

The present invention (5) relates also to the pressure-sensitiveadhesive sheet for surface protection (1 to 4), wherein the layer Acontains an ultraviolet absorber in an amount of 0.05 to 0.5% by weightbased on the total weight of the layer A.

BEST MODE FOR CARRYING OUT THE INVENTION

The layer A according to the present invention contains 60 to 100% byweight of polyethylene based on the total weight of the layer A. Here,the polyethylene used in the layer A preferably has a density of 0.91 to0.97, a melt flow rate (hereinafter abbreviated as MFR; ASTM D1238) of0.02 to 30 g/10 minutes (190° C.; load: 2.16 kg), more preferably an MFRof 0.1 to 10 g/10 minutes in view of film forming properties,flexibility of resulting adhesive sheet, etc.

Other components that can be contained in the layer A include, forexample, polymers other than polyethylene and additives. Other polymersinclude a blend of at least one kind of component selected from thegroup consisting of polypropylenes, ethylene/propylene copolymers,ethylene/propylene/diene type hydrocarbon copolymers, ethylene/butene-1copolymers, ethylene/α-olefin copolymers, ethylene/methacryliccopolymers, metal salts of ethylene/methacrylic copolymers,ethylene/methyl (meth)acrylate copolymers, ethylene/ethyl (meth)acrylatecopolymers, ethylene/vinyl acetate copolymers, olefin crystal/dienehydrocarbon/olefin crystal block copolymers (including hydrogenatedproducts thereof), styrene/diene type hydrocarbon/olefin crystal blockcopolymers (including hydrogenated products thereof), styrene/diene typehydrocarbon/styrene block copolymers (including hydrogenated productsthereof) and styrene/diene type hydrocarbon random copolymers (includinghydrogenated products thereof). Other polymers are preferably thosehaving an MFR of 0.1 to 30 g/10 minutes (190° C.; load: 2.16 kg) orthose having an MFR of 0.5 to 30 g/10 minutes (230° C.; load: 2.16 kg)in view of compatibility with the base polymer, film forming propertiesand the like.

Further, in view of weathering resistance, the layer A preferablycontains an ultraviolet absorber in an amount of 0.05 to 0.5% by weightbased on the total weight of the layer A. The ultraviolet absorberincludes, for example, benzotriazole compounds which may be used singlyor as a blend of two or more kinds of them.

The layer B according to the present invention contains a polypropylenetype polymer in an amount of 50 to 100% by weight based on the totalweight of the layer B. Here, the polypropylene type polymer to becontained in the layer B includes, for example, homopolypropylenes andethylene/propylene copolymers (block copolymers or random copolymerswhich are generally referred to as block polypropylene or randompolypropylenes). Those having an MFR of 0.3 to 10 g/10 minutes (230° C.;load: 2.16 kg) are preferred in view of film forming properties, as wellas, tensile strength and flexibility of the resulting pressure-sensitiveadhesive sheet.

The layer B may contain polymers other than polypropylene polymers andadditives. Other polymers include a blend of at least one kind ofcomponent selected from the group consisting, for example, ofpolyethylenes, ethylene/propylene/diene type hydrocarbon copolymers,ethylene/butene-1-copolymers, ethylene/α-olefin copolymers,ethylene/methacrylic copolymers, metal salts of ethylene/methacryliccopolymers, ethylene/methyl (meth)acrylate copolymers, ethylene/ethyl(meth)acrylate copolymers, ethylene/vinyl acetate copolymers, olefincrystal/diene hydrocarbon/olefin crystal block copolymers (includinghydrogenated products thereof), styrene/diene type hydrocarbon/olefincrystal block copolymers (including hydrogenated products thereof),styrene/diene type hydrocarbon/styrene block copolymers (includinghydrogenated products thereof) and styrene/diene type hydrocarbon randomcopolymers (including hydrogenated products thereof). Further, thosehaving an MFR of 0.02 to 10 g/10 minutes measured at 190° C. under aload of 2.16 kg or those having an MFR of 0.3 to 10 g/10 minutes (230°C.; load: 2.16 kg) are preferred in view of compatibility with the basepolymer, film forming properties and the like.

The layer C according to the present invention contains a hydrogenatedstyrene/diene type hydrocarbon copolymer in an amount of 10 to 100% byweight based on the total weight of the layer C. The hydrogenatedstyrene/diene type hydrocarbon copolymer contained in the layer C ispreferably a block copolymer or a random copolymer having an MFR of 0.3to 10 g/10 minutes (230° C.;

load: 2.16 kg) and a styrene content of 5 to 40 wt % in view of adhesionwith the pressure-sensitive adhesive layer, film forming properties andthe like. The layer C may contain polymers other than the hydrogenatedstyrene/diene type hydrocarbon copolymer and additives. Other polymersinclude a blend of at least one kind of component selected from thegroup consisting, for example, of polyolefin polymers such aspolyethylenes, polypropylenes, ethylene/propylene copolymers,ethylene/propylene/diene type hydrocarbon copolymers,ethylene/butene-1-copolymers, ethylene/α-olefin copolymers,ethylene/methacrylic copolymers, metal salts of ethylene/methacryliccopolymers, ethylene/methyl (meth)acrylate copolymers, ethylene/ethyl(meth)acrylate copolymers, ethylene/vinyl acetate copolymers, olefincrystal/diene hydrocarbon/olefin crystal block copolymers (includinghydrogenated products thereof) and styrene/diene type hydrocarbon/olefincrystal block copolymers (including hydrogenated products thereof).Further, those having an MFR of 0.1 to 30 g/10 minutes measured at 190°C. under a load of 2.16 kg or those having an MFR of 0.5 to 30 g/10minutes (230° C.; load: 2.16 kg) are preferred in view of compatibilitywith the hydrogenated styrene/diene type hydrocarbon copolymer, filmforming properties and the like.

The layer C preferably contains an ultraviolet stabilizer in an amountof not less than 0.1 part by weight per 100 parts by weight of thehydrogenated styrene/diene type hydrocarbon copolymer contained in thelayer C and not more than 0.5% by weight based on the total weight ofthe layer C. The ultraviolet stabilizer includes, for example, hinderedamine compounds and benzoate compounds, and these compounds may be usedsingly or as a blend of two or more kinds of them.

In the three-layered film (layer A/layer B/layer C) according to thepresent invention, it is preferred that one or two of these three layersor all of them contain titanium dioxide. The three-layered filmpreferably has a total titanium dioxide content of 5 to 20 wt % based onthe total weight of the three-layered film. As the titanium dioxide, asurface-inactivated titanium dioxide treated, for example, with aluminaor silica which hardly forms radicals under ultraviolet irradiation ispreferred in view of weathering resistance. If a surface-activatedtitanium dioxide is used, radicals are formed on the surface of thetitanium dioxide upon ultraviolet irradiation to acceleratedeterioration of the substrate layers. Further, the titanium dioxidepreferably has a particle diameter of 0.1 to 0.4 μm.

All of the layers containing titanium dioxide preferably containadditionally an ultraviolet stabilizer. It is also preferred that eachlayer containing titanium dioxide has an ultraviolet stabilizer contentof not less than 0.5 part by weight per 100 parts by weight of thetitanium dioxide contained therein and not more than 0.5% by weightbased on the total weight of the layer.

The layers A to C may contain various kinds of additives respectivelyother than those described above, so long as they do not impair theintended objective of the present invention. The additives include, forexample, softening agents such as oils, paraffin waxes, epoxyplasticizers and polyester plasticizers; pigments such as titaniumdioxide, carbon black and red oxide; fillers such as talc and calciumcarbonate; lubricants such as stearic acid, stearoyl amide, calciumstearate, barium stearate and zinc stearate; antioxidants such as phenolcompounds, phosphite compounds and thioether compounds; ultravioletabsorbers or stabilizers such as benzotriazole compounds, hindered aminecompounds and benzoate compounds; inorganic hollow p articles such asglass balloons and silica balloons; microspheres of polymer such asacrylic microspheres and high molecular weight polyolefin powders; andreleasability imparting agents such as silicone compounds and long-chainalkyl compounds.

While the pressure-sensitive adhesive layer according to the presentinvention is no t particularly limited, it is preferably a rubber typepressure-sensitive adhesive, particularly preferably at least one kindof component selected from the group consisting of polyisobutylene,butyl rubber and polybutene.

The pressure-sensitive adhesive layer may, as necessary, contain variouskinds of additives so long as they do not impair the intended objectiveof the present invention. The additives include, for example, softeningagents such as oils, paraffin waxes, epoxy plasticizers and polyesterplasticizers; pigments such as titanium dioxide, carbon black and redoxide; fillers such as talc and calcium carbonate; lubricants such asstearic acid, stearoyl amide, calcium stearate, barium stearate and zincstearate; antioxidants such as phenol compounds, phosphite compounds andthioether compounds; ultraviolet absorbers or stabilizers such asbenzotriazole compounds, hindered amine compounds and benzoatecompounds; inorganic hollow particles such as glass balloons and silicaballoons; microspheres of polymers such as acrylic microspheres and highmolecular weight polyolefin powders; and releasability imparting agentssuch as silicone compounds and long-chain alkyl compounds.

Referring to the thickness of the substrate layers, the layers A, B andC have thickness values of preferably 2 to 200 μm, 2 to 400 μm and 2 to200 μm, respectively, more preferably 5 to 50 μm, 10 to 100 μm and 5 to50 μm, respectively. The pressure-sensitive adhesive layer has athickness of preferably 2 to 100 μm. more preferably 5 to 30 μm.

The pressure-sensitive adhesive sheet for surface protection accordingto the present invention is prepared by forming a three-layered filmconsisting of a layer A, a layer B and a layer C. After the film issubjected to one-side corona treatment on the layer A side, theresulting layer A side is treated with a releasing agent, and apressure-sensitive adhesive layer is then formed on the layer C side bymeans of solution coating or hot melt extrusion coating. Alternatively,substrate layers and a pressure-sensitive adhesive layer are coextrudedto form a layer A/layer B/layer C/pressure-sensitive adhesive layer,followed successively by one-side corona treatment and releasing agentapplication treatment on the layer A side in a continuous process.

The present invention will be described below specifically by way ofnonlimitative examples.

Components used are as follows:

-   (1) High-density polyethylene (hereinafter abbreviated as “HPE”)-   HPE-1: HI-ZEX 6800S (high-density polyethylene, manufactured by    Mitsui Chemicals, Inc.)-   (2) Low-density polyethylene (hereinafter abbreviated as “LPE” )-   LPE-1: JF630S (low-density polyethylene, manufactured by JAPAN    POLYOLEFINS Co., Ltd.)-   (3) Polypropylene (hereinafter abbreviated as “HPP”)-   HPP-1: IDEMITSU POLYPRO F-200S (polypropylene, manufactured by    Idemitsu Petrochemical Co., Ltd.)-   (4) Ethylene/propylene copolymer (hereinafter abbreviated as “EPP”-   EPP-1: NOBLEN BJS-M (ethylene/propylene block copolymer,    manufactured by Mitsui Chemicals, Inc.)-   (5) Ethylene/butene-1 copolymer (hereinafter abbreviated as “EBM”)-   EBM-1: JSR EBM2011P (ethylene/butene-1 random copolymer,    manufactured by JSR Corporation)-   (6) Hydrogenated styrene/diene type hydrocarbon copolymer    (hereinafter abbreviated as “HSR”)-   HSR-1: DYNARON 1320P (hydrogenated styrene/butadiene random    copolymer, manufactured by JSR Corporation)-   (7) Titanium dioxide (hereinafter abbreviated as “TIO”)-   TIO-1: TIPAQUE CR90 (rutile type surface-inactivated titanium    dioxide, manufactured by ISHIRARA SANGYO KAISYA, LTD.)-   (8) Ultraviolet stabilizer (hereinafter abbreviated as HLS-   HLS-1: TINUBIN 622LD (hindered amine ultraviolet stabilizer,    manufactured by Ciba Specialty Chemicals)-   (9) Ultraviolet absorber (hereinafter abbreviated as “UVA”)-   UVA-1: TINUVIN 326 (benzotriazole ultraviolet absorber, manufactured    by Ciba Specialty Chemicals)-   (10) Antioxidant (hereinafter abbreviated as “AO”)-   AO-1: IRGANOX 1010 (hindered phenol antioxidant, manufactured by    Ciba Specialty Chemicals)-   (11) Polyisobutylene (hereinafter abbreviated as “PIB”)-   PIB-1: VISTANEX MML80 (polyisobutylene, manufactured by Exxon Corp.;    M_(r,v): 990,000)-   (12) Polybutene (hereinafter abbreviated as “PB”)-   PB-1: IDEMITSU POLYBUTENE 300R (polybutene, manufactured by Idemitsu    Petrochemical Co., Ltd.; M_(n): 1330)

EXAMPLES 1 TO 3 AND COMPARATIVE EXAMPLES 1 TO 6

Compositions shown in Table 1 were coextruded through a T-die extruderto form 60 μm-thick three-layered films having a ratio of layer A/layerB/layer C=10:40:10, respectively. Next, each film was subjected toone-side corona treatment on the layer A side so that the film may havea surface wettability of 50 dyn/cm immediately after the treatment,followed by treatment of the same side with a long-chain alkylreleasability imparting agent. Subsequently, a pressure-sensitiveadhesive containing PIB-1/PB-1/UVA-1/AO-1=70/30/0.5/0.5 (in terms ofweight ratio) in a toluene solvent was applied to the layer C side to athickness of 10 μm by means of solution coating.

TABLE 1 Example Example Example Comparative Comparative ComparativeComparative Comparative Comparative 1 2 3 Example 1 Example 2 Example 3Example 4 Example 5 Example 6 Layer A HPE-1 70.00 65.00 70.00 30.0099.80 30.00 99.88 30.00 30.00 LPE-1 29.80 69.70 EPP-1 29.70 69.70 69.7069.70 TIO-1 34.50 HLS-1 0.20 UVA-1 0.10 0.15 0.15 0.15 0.10 0.15 0.020.15 0.15 AO-1 0.10 0.15 0.15 0.15 0.10 0.15 0.10 0.15 0.15 Layer BHPP-1 60.00 60.00 30.00 30.00 30.00 60.00 67.00 EPP-1 75.00 75.00 EBM-115.00 24.80 24.80 30.00 60.00 60.00 60.00 30.00 30.00 TIO-1 24.70 9.809.80 9.80 9.80 9.88 2.80 HLS-1 0.20 0.10 0.10 0.10 0.10 0.10 0.10 0.020.10 AO-1 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Layer C HPP-140.00 40.00 40.00 EPP-1 75.00 40.00 75.00 97.00 75.00 75.00 HSR-1 59.8024.80 25.00 59.80 24.80 2.80 24.80 59.80 24.80 TIO-1 34.65 HLS-1 0.100.10 0.25 0.10 0.10 0.10 0.10 0.10 AO-1 0.10 0.10 0.10 0.10 0.10 0.100.10 0.10 Titanium 16.5% 5.8% 5.8% 6.5% 6.5% 6.5% 6.5% 6.6% 1.9% dioxidecontent in layers A, B and C *Thickness: Layer A:Layer B:Layer C = 10μm:40 μm:10 μm

The pressure-sensitive adhesive sheets for surface protection obtainedin Examples 1 to 3 and Comparative Examples 1 to 6 were evaluated interms of odor, adhesion between the substrate and adhesive layer,weathering resistance, as well as, application and peeling operability.Odor of the corona-treated films before application of thepressure-sensitive adhesive was also evaluated.

(1) Evaluation of Odor

Odor of each film immediately after the corona treatment and that of thefilm after application of the pressure-sensitive adhesive wereevaluated.

(2) Evaluation of Adhesion between Substrate and Pressure-SensitiveAdhesive Layer

An adhesive cellophane tape (Nichiban Co., Ltd.) was applied to asample, and they were subjected to T-peeling at a rate of 0.3 m/min. toevaluate if the pressure-sensitive adhesive layer of the sample came offor not.

(3) Evaluation of Weathering Resistance

A sample was applied to a poor adherend acrylic paint film, followed byirradiation with carbon arc. The thus treated sample was then subjectedto peeling at a rate of 40 m/min. to evaluate if fracture occurred ornot in the substrate and if dusting due to chalking occurred or notduring the peeling.

(4) Application and Peeling Operability

Operability when the sample was applied to a finished car coated with apoor adherend acrylic paint and operability when the sample was peeledafter 6 month of outdoor exposure from the application were evaluated.

(5) Remarks

Paint film: poor adherend acrylic coating film (containing silicone)having a wettability (JIS K6768) of lower than 30 dyn/cm.

Carbon arc irradiation: 1000 hour irradiation using a sunshine weathermeter (rainfall: 200 hrs.)

Test Result

Test results are shown in Table 2.

TABLE 2 Example Example Example Comparative Comparative ComparativeComparative Comparative Comparative 1 2 3 Example 1 Example 2 Example 3Example 4 Example 5 Example 6 Odor Corona treated film ◯ ◯ ◯ X ◯ ◯ ◯ X XPressure-sensitive ◯ ◯ ◯ X ◯ ◯ ◯ X X adhesive sheet Adhesion between ◯ ◯◯ ◯ ◯ X ◯ ◯ ◯ substrate and pressure- sensitive adhesive layerWeathering resistance Fracture in substrate ◯ ◯ ◯ ◯ ◯ ◯ X X X at peelingChalking ◯ ◯ ◯ X ◯ ◯ ◯ X X Application and peeling ◯ ◯ ◯ ◯ X X X ◯ ◯operability Odor: ◯: little odor X: strong odor Adhesion between thesubstrate and the pressure-sensitive adhesive layer: ◯: no liftingoccurred in the adhesive layer X: lifting occurred in the adhesive layerFracture in the substrate at peeling: ◯: no fracture occurred X:fracture occurred Chalking: ◯: no white powder dusting occurred X: whitepowder dusting occurred Application and peeling operability: ◯:excellent X: poor operability due to the pressure-sensitive adhesivesheet being too soft

As is clear from Table 2, the pressure-sensitive adhesive sheet forsurface protection according to the present invention has excellentweathering resistance and can be peeled easily causing neither dustingof white powder particles due to chalking nor fracture in the substrateeven when the sheet is peeled speedily after carbon arc irradiation. Thesheet of the present invention also has excellent adhesion between thesubstrate and the pressure-sensitive adhesive layer, enables extendedapplication operation due to reduced corona odor and can be applied andpeeled with no difficulty.

1. A pressure-sensitive adhesive sheet for surface protection comprisinga three-layered film in which a layer A, a layer B and a layer C havebeen laminated in this order and a pressure-sensitive adhesive layer onthe layer C; wherein the layer A contains a polyethylene polymer in anamount of at least 60% by weight based on a total weight of the layer A;the layer B contains an ethylene/propylene copolymer in an amount of atleast 50% by weight based on a total weight of the layer B; and thelayer C contains a hydrogenated styrene/diene hydrocarbon randomcopolymer in an amount of at least 10% by weight based on a total weightof the layer C.
 2. The pressure-sensitive adhesive sheet for surfaceprotection according to claim 1, wherein the layer C contains anultraviolet stabilizer in an amount of not less than 0.1 part by weightper 100 parts by weight of the hydrogenated styrene/diene hydrocarbonrandom copolymer contained in the layer C and not more than 0.5% byweight based on the total weight of the layer C.
 3. Thepressure-sensitive adhesive sheet for surface protection according toclaim 1 or 2, wherein at least one layer in the three-layered filmcontains titanium dioxide, and the three-layered film has a totaltitanium dioxide content of 5 to 20% by weight based on the total weightof the three-layered film.
 4. The pressure-sensitive adhesive sheet forsurface protection according to claim 3, wherein the layers containingtitanium dioxide all further contain an ultraviolet stabilizer, and eachtitanium dioxide-containing layer contains the ultraviolet stabilizer inan amount of not less than 0.5 part by weight per 100 parts by weight ofthe titanium dioxide contained in that layer and not more than 0.5% byweight based on the total weight of that layer.
 5. Thepressure-sensitive adhesive sheet for surface protection according toclaim 1, wherein the layer A contains an ultraviolet absorber in anamount of 0.05 to 0.5% by weight based on the total weight of the layerA.
 6. The pressure-sensitive adhesive sheet for surface protectionaccording to claim 2, wherein the layer A contains an ultravioletabsorber in an amount of 0.05 to 0.5% by weight based on the totalweight of the layer A.
 7. The pressure-sensitive adhesive sheet forsurface protection according to claim 3, wherein the layer A contains anultraviolet absorber in an amount of 0.05 to 0.5% by weight based on thetotal weight of the layer A.
 8. The pressure-sensitive adhesive sheetfor surface protection according to claim 4, wherein the layer Acontains an ultraviolet absorber in an amount of 0.05 to 0.5% by weightbased on the total weight of the layer A.
 9. The pressure-sensitiveadhesive sheet for surface protection according to claim 1, wherein thelayer B further contains an ethylene/butene-1 copolymer.
 10. Thepressure-sensitive adhesive sheet for surface protection according toclaim 1, wherein the pressure-sensitive adhesive layer comprises arubber type pressure sensitive adhesive.
 11. The pressure-sensitiveadhesive sheet for surface protection according to claim 10, wherein therubber type pressure-sensitive adhesive comprises at least one componentselected from the group consisting of polyisobutylene, butyl rubber andpolybutene.